Curable resin composition and cured product thereof, encapsulant, and semiconductor device

ABSTRACT

Provided is a curable resin composition capable of forming a cured product that has excellent heat resistance and transparency and, in particular, offers excellent barrier properties to a corrosive gas. 
     The curable resin composition according to the present invention includes a polyorganosiloxane (A), an isocyanurate compound (B), and a silane coupling agent (C). The polyorganosiloxane (A) is an aryl-containing polyorganosiloxane. The polyorganosiloxane (A) preferably includes a polyorganosiloxane having a number-average molecular weight (Mn) of 500 to 4000 as determined by gel permeation chromatography and calibrated with a polystyrene standard.

TECHNICAL FIELD

The present invention relates to curable resin compositions; as well ascured products, encapsulants, and semiconductor devices obtained usingthe curable resin compositions. The present application claims priorityto Japanese Patent Application No. 2013-026947 filed in Japan on Feb.14, 2013, the entire contents of which are incorporated herein byreference.

BACKGROUND ART

Semiconductor devices require high heat resistance and high breakdownvoltage, in which semiconductor elements are covered or encapsulated bymaterials. These materials generally require such heat resistance as toendure heat at a temperature of about 150° C. or higher. In particular,materials (encapsulants) to cover or encapsulate optical elements suchas optical semiconductor elements require excellent physical propertiessuch as transparency and flexibility, in addition to the heatresistance. Such encapsulants currently used typically in backlightunits of liquid crystal displays are exemplified by epoxy resinmaterials and silicone resin materials.

Patent Literature (PTL) 1 discloses a synthetic high-molecular compoundas a material having high heat resistance and dissipating heatsatisfactorily. The synthetic high-molecular compound contains at leastone third organosilicon polymer having a molecular weight of from 20000to 800000. The third organosilicon polymer has been formed by linking atleast one first organosilicon polymer with at least one secondorganosilicon polymer through siloxane bonds. The first organosiliconpolymer has a crosslinked siloxane structure, where the siloxanestructure refers to a Si—O—Si bonded structure. The second organosiliconpolymer has a linear linked siloxane structure. Materials of this type,however, are still insufficient in physical properties.

PTL 2 discloses a resin composition for optical element encapsulation asa resin composition that excels in transparency, ultraviolet resistance,and thermal coloration resistance and is used for the encapsulation ofan optical element. The resin composition contains, as a resincomponent, at least one silsesquioxane selected from the groupconsisting of liquid silsesquioxanes having a cage-like structure,containing an aliphatic carbon-carbon unsaturated bond, and being devoidof H—Si bonds; and liquid silsesquioxanes having a cage-like structure,containing a H—Si bond, and being devoid of aliphatic carbon-carbonunsaturated bonds. Unfortunately, however, the resin compositioncontaining such a cage-like silsesquioxane gives a cured product that isrelatively rigid, is poorly flexible, and is susceptible to crackingand/or fracture.

PTL 3 discloses a curable composition that essentially contains anorganic compound containing at least two carbon-carbon double bonds permolecule, a compound containing at least two SiH groups per molecule,and a hydrosilylation catalyst, where the carbon-carbon double bonds arereactive with SiH groups. The organic compound is exemplified bytriallyl isocyanurate. The compound containing at least two SiH groupsper molecule is exemplified by chain and/or cyclic polyorganosiloxanes.Disadvantageously, however, materials of this type are stillinsufficient in physical properties such as cracking resistance.

CITATION LIST Patent Literature

PTL 1: Japanese Unexamined Patent Application Publication (JP-A) No.2006-206721

PTL 2: JP-A No. 2007-031619

PTL 3: JP-A No. 2002-314140

SUMMARY OF INVENTION Technical Problem

In addition to the heat resistance, transparency, and flexibility,encapsulants for optical semiconductor elements require resistance todeterioration even upon the application of heat at a high temperature ina reflow process in the production of optical semiconductor devices.Specifically, the encapsulants require such properties as to resistcracking and not to cause troubles such as detachment from the package.These properties are also generically referred to as “reflowresistance”. As used herein the term “cracking resistance” refers tosuch a property of an encapsulant as to resist cracking.

In addition, the encapsulants for optical semiconductor elements requirehigh barrier properties to a corrosive gas such as a SO_(X) gas. This isbecause metal materials typically of electrodes in the opticalsemiconductor devices are readily corroded by the corrosive gas and,once corroded, disadvantageously deteriorate in electrical properties(e.g., electrical properties in a high-temperature environment) withtime. Encapsulants using the conventional silicone resin materials arewidely used as the encapsulants for optical semiconductor elements.Unfortunately, the encapsulants of this type have insufficient barrierproperties to a corrosive gas. Likewise, the materials described in PTL1 to 3 disadvantageously have insufficient barrier properties to acorrosive gas.

Accordingly, it is an object of the present invention to provide acurable resin composition capable of forming a cured product that hasexcellent heat resistance and transparency and, in particular, offersexcellent barrier properties to a corrosive gas.

It is another object of the present invention to provide a cured productand an encapsulant, both of which have excellent heat resistance andtransparency and, in particular, offer excellent barrier properties to acorrosive gas.

It is yet another object of the present invention to provide asemiconductor device that includes at least one of the cured product andthe encapsulant (either one or both of the cured product and theencapsulant).

Solution to Problem

The present inventors have found a curable resin composition includingan aryl-containing polyorganosiloxane incorporated with an isocyanuratecompound and a silane coupling agent; and have found that this curableresin composition can form a cured product that has excellent heatresistance, transparency, and flexibility and, in particular, offersexcellent reflow resistance and barrier properties to a corrosive gas.The present invention has been made based on these findings.

Specifically, the present invention provides a curable resin compositionincluding a polyorganosiloxane (A), an isocyanurate compound (B), and asilane coupling agent (C). The polyorganosiloxane (A) is anaryl-containing polyorganosiloxane.

In the curable resin composition, the polyorganosiloxane (A) may includea polyorganosiloxane having a number-average molecular weight (Mn) offrom 500 to 4000 as determined by gel permeation chromatography andcalibrated with a polystyrene standard.

The polyorganosiloxane (A) in the curable resin composition may includea polyorganosiloxane having a molecular-weight dispersity (Mw/Mn) offrom 0.95 to 4.00, where the polyorganosiloxane has a weight-averagemolecular weight of Mw and a number-average molecular weight of Mn asdetermined by gel permeation chromatography and calibrated with apolystyrene standard.

The polyorganosiloxane (A) in the curable resin composition may includea polyorganosiloxane (A1) containing an aliphatic carbon-carbon doublebond.

The polyorganosiloxane (A) in the curable resin composition may includea polyorganosiloxane (A2) containing a Si—H bond.

The polyorganosiloxane (A) in the curable resin composition may contain50 percent by weight or more of the polyorganosiloxane (A2) containing aSi—H bond based on the total amount (100 percent by weight) of thepolyorganosiloxane (A).

The isocyanurate compound (B) in the curable resin composition mayinclude an isocyanurate compound represented by Formula (1):

where R^(x), R^(y), and R^(z) are each, identically or differently,selected from a group represented by Formula (2) and a group representedby Formula (3):

where R¹ and R² are each, identically or differently, selected fromhydrogen and C₁-C₈ straight or branched chain alkyl.

In the curable resin composition, at least one of R^(x), R^(y), andR^(z) in Formula (1) may be the group represented by Formula (3).

The present invention provides, in another aspect, a cured product ofthe curable resin composition.

The present invention provides, in yet another aspect, an encapsulantobtained by using the curable resin composition.

In addition and advantageously, the present invention provides asemiconductor device obtained by using the curable resin composition.

Specifically, the present invention relates to followings.

[1] A curable resin composition that includes a polyorganosiloxane (A),an isocyanurate compound (B), and a silane coupling agent (C). Thepolyorganosiloxane (A) is an aryl-containing polyorganosiloxane.

[2] In the curable resin composition according to [1], thepolyorganosiloxane (A) may include a branched-chain-containingpolyorganosiloxane.

[3] In the curable resin composition according to one of [1] and [2],the polyorganosiloxane (A) may contain aryl groups in a content (interms of phenyl) of 35 percent by weight or more based on the totalamount (100 percent by weight) of the polyorganosiloxane (A).

[4] In the curable resin composition according to any one of [1] to [3],the polyorganosiloxane (A) may include a polyorganosiloxane having anumber-average molecular weight (Mn) of from 500 to 4000 as determinedby gel permeation chromatography and calibrated with a polystyrenestandard.

[5] In the curable resin composition according to any one of [1] to [4],the polyorganosiloxane [A] may include a polyorganosiloxane having anumber-average molecular weight (Mn) of from 500 to 1000 as determinedby gel permeation chromatography and calibrated with a polystyrenestandard.

[6] In the curable resin composition according to any one of [1] to [5],the polyorganosiloxane (A) may include a polyorganosiloxane having amolecular-weight dispersity (Mw/Mn) of from 0.95 to 4.00, where thepolyorganosiloxane has a weight-average molecular weight of Mw and anumber-average molecular weight of Mn as determined by gel permeationchromatography and calibrated with a polystyrene standard.

[7] The curable resin composition according to any one of [1] to [6] maycontain the polyorganosiloxane (A) in a content (blending quantity) offrom 55 to 99.5 percent by weight based on the total amount (100 percentby weight) of the curable resin composition.

[8] In the curable resin composition according to any one of [1] to [7],the polyorganosiloxane (A) may include a polyorganosiloxysilalkylene.

[9] In the curable resin composition according to [8], thepolyorganosiloxysilalkylene may include a polyorganosiloxysilalkylenehaving a structure represented by Formula (I) mentioned later.

[10] In the curable resin composition according to one of [8] and [9],the polyorganosiloxane (A) may contain the polyorganosiloxysilalkylenein a proportion of from 60 to 100 percent by weight based on the totalamount (100 percent by weight) of the polyorganosiloxane (A).

[11] In the curable resin composition according to any one of [1] to[10], the polyorganosiloxane (A) may include a polyorganosiloxane (A1)containing an aliphatic carbon-carbon double bond.

[12] In the curable resin composition according to [11], thepolyorganosiloxane (A1) may include a polyorganosiloxysilalkylenecontaining an aliphatic carbon-carbon double bond in molecule.

[13] In the curable resin composition according to [12], thepolyorganosiloxysilalkylene containing an aliphatic carbon-carbon doublebond in molecule may include a polyorganosiloxysilalkylene thatcontains, at its terminus and/or side chain, a group containing analiphatic carbon-carbon double bond.

[14] In the curable resin composition according to [13], thepolyorganosiloxysilalkylene containing an aliphatic carbon-carbon doublebond in molecule may include a polyorganosiloxysilalkylene thatcontains, at its terminus and/or side chain, a group containing analiphatic carbon-carbon double bond and includes the structurerepresented by Formula (I).

[15] In the curable resin composition according to any one of [11] to[14], the polyorganosiloxane (A) may contain the aliphatic carbon-carbondouble bond in a content (in terms of vinyl) of from 1.5 to 15.0 percentby weight based on the total amount (100 percent by weight) of thepolyorganosiloxane (A).

[16] In the curable resin composition according to any one of [11] to[15], the polyorganosiloxane (A1) may include, as an essentialcomponent, a polyorganosiloxane (A1) having an aliphatic carbon-carbondouble bond content (in terms of vinyl) of 10.0 percent by weight ormore.

[17] In the curable resin composition according to [16], thepolyorganosiloxane (A1) having an aliphatic carbon-carbon double bondcontent (in terms of vinyl) of 10.0 percent by weight or more may have aweight-average molecular weight of 2000 or less.

[18] In the curable resin composition according to one of [16] and [17],the polyorganosiloxane (A1) having an aliphatic carbon-carbon doublebond content (in terms of vinyl) of 10.0 percent by weight or more mayhave a number-average molecular weight of 1000 or less.

[19] In the curable resin composition according to any one of [16] to[18], the polyorganosiloxane (A) may contain the polyorganosiloxane (A1)having an aliphatic carbon-carbon double bond content (in terms ofvinyl) of 10.0 percent by weight or more in a proportion of 1 to 10percent by weight based on the total amount (100 percent by weight) ofthe polyorganosiloxane (A).

[20] In the curable resin composition according to any one of [1] to[19], the polyorganosiloxane (A) may include a polyorganosiloxane (A2)containing a Si—H bond (Si—H-bond-containing polyorganosiloxane (A2)).

[21] In the curable resin composition according to [20], thepolyorganosiloxane (A2) may include a polyorganosiloxysilalkylenecontaining a Si—H bond in molecule.

[22] In the curable resin composition according to [21], thepolyorganosiloxysilalkylene containing a Si—H bond in molecule mayinclude a polyorganosiloxysilalkylene that contains, at its terminusand/or side chain, hydrogen (hydrido) bonded to silicon.

[23] In the curable resin composition according to one of [21] and [22],the polyorganosiloxysilalkylene containing a Si—H bond in molecule mayinclude a polyorganosiloxysilalkylene that contains, at its terminusand/or side chain, hydrogen bonded to silicon and has the structurerepresented by Formula (I).

[24] In the curable resin composition according to any one of [20] to[23], the polyorganosiloxane (A) may contain the Si—H bond in a contentin terms of H of from 0.01 to 0.50 percent by weight based on the totalamount (100 percent by weight) of the polyorganosiloxane (A), where theterm “in terms of H” refers to “in terms of the weight of hydrogen atomor H (hydrido) in Si—H bond”.

[25] In the curable resin composition according to any one of [20] to[24], the polyorganosiloxane (A) may contain 50 percent by weight ormore of the polyorganosiloxane (A2) containing a Si—H bond based on thetotal amount (100 percent by weight) of the polyorganosiloxane (A).

[26] In the curable resin composition according to any one of [1] to[25], the isocyanurate compound (B) may include an isocyanurate compoundrepresented by Formula (1), in which R^(x), R^(y), and R^(z) are each,identically or differently, selected from a group represented by Formula(2) and a group represented by Formula (3).

[27] In the curable resin composition according to [26], at least one ofR^(x), R^(y), and R^(z) in Formula (1) may be the group represented byFormula (3).

[28] In the curable resin composition according to one of [26] and [27],it is preferred that two of R^(x), R^(y), and R^(z) are the groupsrepresented by Formula (2) and the other one of R^(x), R^(y), and R^(z)is the group represented by Formula (3).

[29] The curable resin composition according to any one of [1] to [28]may contain the isocyanurate compound (B) in a content of from 0.01 to10 percent by weight based on the total amount (100 percent by weight)of the curable resin composition.

[30] The curable resin composition according to any one of [1] to [29]may contain the isocyanurate compound (B) in a content of from greaterthan 0.5 percent by weight to 10 percent by weight based on the totalamount (100 percent by weight) of the curable resin composition.

[31] In the curable resin composition according to any one of [1] to[30], the silane coupling agent (C) may include an epoxy-containingsilane coupling agent.

[32] The curable resin composition according to any one of [1] to [31]may contain the silane coupling agent (C) in a content of from 0.01 to15 percent by weight based on the total, amount (100 percent by weight)of the curable resin composition.

[33] The curable resin composition according to any one of [1] to [32]may contain the silane coupling agent (C) in a content of from greaterthan 2.0 percent by weight to 15 percent by weight based on the totalamount (100 percent by weight) of the curable resin composition.

[34] The curable resin composition according to any one of [1] to [33]may have such a formulation (blending formulation) that an aliphaticcarbon-carbon double bond is present in an amount of from 0.2 to 4 molesper mole of hydrosilyl groups present in the curable resin composition.

[35] The curable resin composition according to any one of [1] to [34]may have a viscosity of from 300 to 20000 mPa·s at 23° C.

[36] A cured product obtained by curing the curable resin compositionaccording to any one of [1] to [35].

[37] An encapsulant obtained by using the curable resin compositionaccording to any one of [1] to [35].

[38] A semiconductor device obtained by using the curable resincomposition according to any one of [1] to [35].

[39] The semiconductor device according to [38] may be an opticalsemiconductor device.

Advantageous Effects of Invention

The curable resin composition according to the present invention, ashaving the configuration, excels particularly in barrier properties to acorrosive gas such as a SO_(X) gas. In addition, the cured product, asincluding a silicone material, excels also in heat resistance andtransparency. Accordingly, the curable resin composition according tothe present invention is preferably usable as or for an encapsulant foroptical semiconductor element encapsulation. The optical semiconductorelement is exemplified by light-emitting diodes (LEDs), semiconductorlaser elements, solar photovoltaic devices, and charge coupled devices(CODs). When the cured product of the curable resin compositionaccording to the present invention is used for encapsulation of such anoptical semiconductor element to give an optical semiconductor device,the resulting optical semiconductor device has excellent quality anddurability. In particular, the curable resin composition according tothe present invention is useful as or for an encapsulant for anext-generation light source which requires resistance to heat at anunprecedented high temperature (e.g., 180° C. or higher).

DESCRIPTION OF EMBODIMENTS

The curable resin composition according to the present invention is acurable resin composition including a polyorganosiloxane (A), anisocyanurate compound (B), and a silane coupling agent (C) as essentialcomponents. The polyorganosiloxane (A) is an aryl-containingpolyorganosiloxane.

Polyorganosiloxane (A)

The polyorganosiloxane (A) in the curable resin composition according tothe present invention is a polyorganosiloxane having a main chainincluding siloxane bonds (Si—O—Si) and containing an aryl group as asubstituent in the main chain. The polyorganosiloxane (A) may include apolyorganosiloxane having a straight chain and/or a branched chain.Among them, the polyorganosiloxane (A) preferably includes apolyorganosiloxane containing a branched chain from the viewpoint of thestrength of the cured product.

The aryl group in the polyorganosiloxane (A) is exemplified by, but notlimited to, C₆-C₁₄ aryl such as phenyl and naphthyl, of which C₆-C₁₀aryl is preferred. The aryl group may also be a substituent on siliconatom in the polyorganosiloxane (A). The substituent herein refers to agroup bonded directly to the silicon atom.

The aryl group in the polyorganosiloxane (A) may have one or moresubstituents. The substituents are exemplified by halogen, substitutedor unsubstituted hydrocarbon groups, hydroxy, alkoxy, alkenyloxy,aryloxy, aralkyloxy, acyloxy, mercapto (thiol group), alkylthio,alkenylthio, arylthio, aralkylthio, carboxy, alkoxycarbonyl,aryloxycarbonyl, aralkyloxycarbonyl, amino or substituted amino (e.g.,mono- or di-alkylamino and acylamino), epoxy, cyano, isocyanato,carbamoyl, and isothiocyanato.

The substituted or unsubstituted hydrocarbon groups are exemplified byaliphatic hydrocarbon groups, alicyclic hydrocarbon groups, aromatichydrocarbon groups, and groups each including two or more of them bondedto each other.

The aliphatic hydrocarbon groups are exemplified by alkyl, alkenyl, andalkynyl. The alkyl is exemplified by C₁-C₂₀ alkyl such as methyl, ethyl,propyl, isopropyl, butyl, hexyl, octyl, isooctyl, decyl, and dodecyl, ofwhich C₁-C₁₀ alkyl is preferred, and C₁-C₄ alkyl is more preferred. Thealkenyl is exemplified by C₂-C₂₀ alkenyl such as vinyl, allyl,methallyl, 1-propenyl, isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl,1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, and 5-hexenyl, of whichC₂-C₁₀ alkenyl is preferred, and C₂-C₄ alkenyl is more preferred. Thealkynyl is exemplified by C₂-C₂₀ alkynyl such as ethynyl and propynyl,of which C₂-C₁₀ alkynyl is preferred, and C₂-C₄ alkynyl is morepreferred.

The alicyclic hydrocarbon groups are exemplified by C₃-C₁₂ cycloalkylsuch as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, andcyclododecyl; C₃-C₁₂ cycloalkenyl such as cyclohexenyl; and C₄-C₁₅bridged hydrocarbon groups such as bicycloheptyl and bicycloheptenyl.

The aromatic hydrocarbon groups are exemplified by C₆-C₁₄ aryl such asphenyl and naphthyl, of which C₆-C₁₀ aryl is preferred.

The groups each including the aliphatic hydrocarbon group and thealicyclic hydrocarbon group bonded to each other are exemplified bycyclohexylmethyl and methylcyclohexyl. The groups each including thealiphatic hydrocarbon group and the aromatic hydrocarbon group bonded toeach other are exemplified by C₇-C₁₈ aralkyl such as benzyl andphenethyl, of which C₇-C₁₀ aralkyl is preferred; (C₆-C₁₀ aryl)-C₂-C₆alkenyl such as cinnamyl; (C₁-C₄ alkyl)-substituted aryl such as tolyl;and (C₂-C₄ alkenyl)-substituted aryl such as styryl. The substituents ofthe substituted hydrocarbon groups (hydrocarbon groups substituted withone or more substituents) are as with the substituents which the arylgroup may have.

The one or more substituents which the aryl group in thepolyorganosiloxane (A) may have are further exemplified by a grouprepresented by Formula (4):

In Formula (4), plural (three) occurrences of R′ may be identical ordifferent. R′ in Formula (4) is, independently in each occurrence,selected typically from hydrogen, halogen, substituted or unsubstitutedhydrocarbon groups, hydroxy, alkoxy, alkenyloxy, aryloxy, aralkyloxy,acyloxy, mercapto (thiol group), alkylthio, alkenylthio, arylthio,aralkylthio, carboxy, alkoxycarbonyl, aryloxycarbonyl,aralkyloxycarbonyl, amino or substituted amino (e.g., mono- ordi-alkylamino and acylamino), epoxy, cyano, isocyanato, carbamoyl, andisothiocyanato.

In the group represented by Formula (4), R′ is, independently in eachoccurrence, preferably selected from hydrogen, C₁-C₁₀ alkyl (inparticular, C₁-C₄ alkyl), C₂-C₁₀ alkenyl (in particular, C₂-C₄ alkenyl),C₃-C₁₂ cycloalkyl, C₃-C₁₂ cycloalkenyl, C₆-C₁₄ aryl which may have oneor more substituents (e.g., C₁-C₄ alkyl, C₂-C₄ alkenyl, halogen, andC₁-C₄ alkoxy) on the aromatic ring, C₇-C₁₈ aralkyl, (C₆-C₁₀ aryl)-C₂-C₆alkenyl, hydroxy, C₁-C₆ alkoxy, and halogen.

The polyorganosiloxane (A) may contain the aryl group in a content (interms of phenyl) not critical, but preferably 35 percent by weight ormore, more preferably 40 percent by weight or more, and furthermorepreferably 45 percent by weight or more (e.g., from 45 to 70 percent byweight), based on the total amount (100 percent by weight) of thepolyorganosiloxane (A). The polyorganosiloxane (A), if containing thearyl group in a content less than 35 percent by weight, may cause theresulting cured product to have lower barrier properties to a corrosivegas such as SO_(X). The aryl group may occupy all or part of thesubstituents on the main chain of the polyorganosiloxane (A), where themain chain includes siloxane bonds (Si—O—Si). The aryl content may bemeasured typically by ¹H-NMR.

The polyorganosiloxane (A) may also contain one or more substituentsother than aryl groups, and the substituents other than aryl groups mayeach be substituents on the silicon atom in the polyorganosiloxane (A).The substituents other than aryl groups are exemplified by hydrogen,halogen, Si—H bond-containing groups, substituted or unsubstitutedhydrocarbon groups (of which alkyl, alkenyl, cycloalkyl, andcycloalkenyl are preferred), hydroxy, alkoxy, alkenyloxy, acyloxy,mercapto (thiol group), alkylthio, alkenylthio, carboxy, alkoxycarbonyl,amino or substituted amino (e.g., mono- or di-alkylamino and acylamino),epoxy, cyano, isocyanato, carbamoyl, and isothiocyanato.

Of the substituents other than aryl groups in the polyorganosiloxane(A), particularly preferred is at least one substituent selected fromhydrogen, Si—H bond-containing groups (e.g., hydrosilyl), andsubstituted or unsubstituted hydrocarbon groups (of which alkyl andalkenyl are preferred).

The polyorganosiloxane (A) may have a number-average molecular weight(Mn) not critical, but preferably from 500 to 4000, more preferably from550 to 2800, furthermore preferably from 600 to 1500, and particularlypreferably 1000 or less. The polyorganosiloxane (A) may have aweight-average molecular weight (Mw) not critical, but preferably from500 to 20000, more preferably from 600 to 10000, and furthermorepreferably from 700 to 6500. The polyorganosiloxane (A), if having anumber-average molecular weight (Mn) and/or a weight-average molecularweight (Mw) less than 500, may cause the resulting cured product to havelower heat resistance. In particular, the polyorganosiloxane (A), whenhaving a number-average molecular weight of 1000 or less, may readilyallow the cured product to have still better barrier properties to acorrosive gas. In contrast, the polyorganosiloxane (A), if having anumber-average molecular weight (Mn) greater than 4000 and/or aweight-average molecular weight (Mw) greater than 20000, may have lowercompatibility with another component, and/or may have lowercompatibility with another polyorganosiloxane (A) in the case where thecomposition includes two or more different polyorganosiloxanes (A). Thepolyorganosiloxane (A) may also be a mixture including those havingdifferent number-average molecular weights (Mn) and/or differentweight-average molecular weights (Mw) within the range. Thenumber-average molecular weight (Mn) and the weight-average molecularweight (Mw) can be determined by calculation as molecular weightsmeasured by gel permeation chromatography and calibrated with apolystyrene standard.

The polyorganosiloxane (A) may have a molecular-weight dispersity(Mw/Mn) not critical, but preferably from 0.95 to 4.00, more preferablyfrom 1.00 to 3.80, and furthermore preferably from 1.20 to 3.50. Themolecular-weight dispersity (Mw/Mn) is calculated from theweight-average molecular weight (Mw) and the number-average molecularweight (Mn). The polyorganosiloxane (A), if having a molecular-weightdispersity (Mw/Mn) greater than 4.00 (in particular, greater than 3.50),may cause the cured product to have inferior heat resistance and/orlower barrier properties to a corrosive gas such as SO_(X).

The curable resin composition according to the present invention maycontain one or more different polyorganosiloxanes alone or incombination as the polyorganosiloxane (A).

The curable resin composition according to the present invention maycontain the polyorganosiloxane (A) in a content (blending quantity) notcritical, but preferably from 55 to 99.5 percent by weight, morepreferably from 70 to 99.0 percent by weight, and furthermore preferablyfrom 85 to 98.5 percent by weight, based on the total amount (100percent by weight) of the curable resin composition. The curable resincomposition, if containing the polyorganosiloxane (A) in a content lessthan 55 percent by weight, may cause the cured product to have lowercracking resistance. In contrast, the curable resin composition, ifcontaining the polyorganosiloxane (A) in a content greater than 99.5percent by weight, may cause the cured product to have lower barrierproperties to a corrosive gas such as SO_(X).

Of such polyorganosiloxanes (A), particularly preferred is apolyorganosiloxysilalkylene. The term “polyorganosiloxysilalkylene”refers to a polyorganosiloxane including, as its main chain, not onlythe —Si—O— group (siloxy group), but also a —Si-A- group [silalkylenegroup; where A represents alkylene]. The alkylene moiety (the “A”moiety) in the silalkylene group of the polyorganosiloxysilalkylene isexemplified by C₁-C₁₂ straight or branched chain alkylene, of whichC₂-C₄ straight or branched chain alkylene is preferred, and ethylene isparticularly preferred. As compared with a polyorganosiloxane in anarrow sense (polyorganosiloxane having a main chain including —Si—O—groups alone), the polyorganosiloxysilalkylene less forms alow-molecular-weight ring upon production process and less decomposesdue typically to heating and resulting silanol group (—SiOH) formation.The polyorganosiloxysilalkylene therefore gives a cured product thattends to less offer surface tack and to less suffer from yellowing. Thepolyorganosiloxysilalkylene may be produced typically by a methoddescribed in JP-A No. 2012-140617. The polyorganosiloxysilalkylene(aryl-containing polyorganosiloxysilalkylene) may also be available asproducts typically under the trade names of GD-1130A and GD-1130B (eachfrom Eternal Chemical Co., Ltd.).

More specifically, the polyorganosiloxysilalkylene is exemplified by apolyorganosiloxysilalkylene having a structure represented by Formula(I):

In Formula (I), R^(a), R^(b), R^(c), R^(d), R^(e), and R^(f) (R^(a) toR^(f)) are, independently in each occurrence, selected from hydrogen, amonovalent hydrocarbon group, and a monovalent heterocyclic group. Atleast one of R^(a) to R^(f) may be selected from hydrogen and amonovalent group including an aliphatic carbon-carbon unsaturated bond.The polyorganosiloxysilalkylene having the structure represented byFormula (I) is one containing an aryl group in molecule. For thisreason, part or all of R^(a) to R^(f) are preferably aryl groups (ofwhich phenyl is more preferred).

The monovalent hydrocarbon group is exemplified by monovalent aliphatichydrocarbon groups; monovalent alicyclic hydrocarbon groups; monovalentaromatic hydrocarbon groups; and monovalent groups each including two ormore of aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, andaromatic hydrocarbon groups bonded to each other. The monovalentheterocyclic group is exemplified by pyridyl, furyl, and thienyl.

The monovalent aliphatic hydrocarbon groups are exemplified by alkyl,alkenyl, and alkynyl. The alkyl is exemplified by straight or branchedchain C₁-C₂₀ alkyl such as methyl, ethyl, propyl, isopropyl, butyl,hexyl, octyl, isooctyl, decyl, and dodecyl, of which C₁-C₁₀ alkyl ispreferred, and C₁-C₄ alkyl is more preferred. The alkenyl is exemplifiedby C₂-C₂₀ alkenyl such as vinyl, allyl, methallyl, 1-propenyl,isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl,3-pentenyl, 4-pentenyl, and 5-hexenyl, of which C₂-C₁₀ alkenyl ispreferred, and C₂-C₄ alkenyl is more preferred. The alkynyl isexemplified by C₂-C₂₀ alkynyl such as ethynyl and propynyl, of whichC₂-C₁₀ alkynyl is preferred, and C₂-C₄ alkynyl is more preferred.

The monovalent alicyclic hydrocarbon groups are exemplified by C₃-C₁₂cycloalkyl such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, andcyclododecyl; C₃-C₁₂ cycloalkenyl such as cyclohexenyl; and C₄-C₁₅bridged hydrocarbon groups such as bicycloheptyl and bicycloheptenyl.

The monovalent aromatic hydrocarbon groups are exemplified by C₆-C₁₄aryl such as phenyl, naphthyl, and anthryl, of which C₆-C₁₀ aryl ispreferred.

The groups each including an aliphatic hydrocarbon group and analicyclic hydrocarbon group bonded to each other is exemplified bycyclohexylmethyl and methylcyclohexyl. The groups each including analiphatic hydrocarbon group and an aromatic hydrocarbon group bonded toeach other is exemplified by C₇-C₁₈ aralkyl such as benzyl andphenethyl, of which C₇-C₁₀ aralkyl is preferred; (C₆-C₁₀ aryl)-C₂-C₆alkenyl such as cinnamyl; (C₁-C₄ alkyl)-substituted aryl such as tolyl;and (C₂-C₄ alkenyl)-substituted aryl such as styryl.

The monovalent hydrocarbon group may have one or more substituents.Specifically, the monovalent hydrocarbon group may be a monovalenthydrocarbon group corresponding to any of the above-exemplifiedmonovalent hydrocarbon groups, except with at least one hydrogen atomsubstituted with a substituent. The substituent(s) may contain carbonatoms in a number of preferably from 0 to 20, and more preferably from 0to 10. Specifically, the substituent(s) is exemplified by halogen;hydroxy; alkoxy; alkenyloxy; aryloxy; aralkyloxy; acyloxy; mercapto;alkylthio; alkenylthio; arylthio; aralkylthio; carboxy; alkoxycarbonyl;aryloxycarbonyl; aralkyloxycarbonyl; amino; mono- or di-alkylamino;mono- or di-phenylamino; acylamino; epoxy-containing groups;oxetanyl-containing groups; acyl; oxo; isocyanato; and groups eachincluding two or more of them bonded to each other, where necessary,through C₁-C₆ alkylene.

The alkoxy is exemplified by C₁-C₆ alkoxy such as methoxy, ethoxy,propoxy, isopropyloxy, butoxy, and isobutyloxy, of which C₁-C₄ alkoxy ispreferred. The alkenyloxy is exemplified by C₂-C₆ alkenyloxy such asallyloxy, of which C₂-C₄ alkenyloxy is preferred. The aryloxy isexemplified by C₆-C₁₄ aryloxy which may have one or more substituents(e.g., C₁-C₄ alkyl, C₂-C₄ alkenyl, halogen, and C₁-C₄ alkoxy) on thearomatic ring, such as phenoxy, tolyloxy, and naphthyloxy. Thearalkyloxy is exemplified by C₇-C₁₈ aralkyloxy such as benzyloxy andphenethyloxy. The acyloxy is exemplified by C₁-C₁₂ acyloxy such asacetyloxy, propionyloxy, (meth)acryloyloxy, and benzoyloxy.

The alkylthio is exemplified by C₁-C₆ alkylthio such as methylthio andethylthio, of which C₁-C₄ alkylthio is preferred. The alkenylthio isexemplified by C₂-C₆ alkenylthio such as allylthio, of which C₂-C₄alkenylthio is preferred. The arylthio is exemplified by C₆-C₁₄ arylthiowhich may have one or more substituents (e.g., C₁-C₄ alkyl, C₂-C₄alkenyl, halogen, and C₁-C₄ alkoxy) on the aromatic ring, such asphenylthio, tolylthio, and naphthylthio. The aralkylthio is exemplifiedby C₇-C₁₈ aralkylthio such as benzylthio and phenethylthio. Thealkoxycarbonyl is exemplified by C₁-C₆ alkoxy-carbonyl such asmethoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, and butoxycarbonyl.The aryloxycarbonyl is exemplified by (C₆-C₁₄ aryloxy)-carbonyl such asphenoxycarbonyl, tolyloxycarbonyl, and naphthyloxycarbonyl. Thearalkyloxycarbonyl is exemplified by (C₇-C₁₈ aralkyloxy)-carbonyl suchas benzyloxycarbonyl. The mono- or di-alkylamino is exemplified by mono-or di-(C₁-C₆ alkyl)amino such as methylamino, ethylamino, dimethylamino,and diethylamino. The acylamino is exemplified by C₁-C₁₁ acylamino suchas acetylamino, propionylamino, and benzoylamino. The epoxy-containinggroups are exemplified by glycidyl, glycidyloxy, and3,4-epoxycyclohexyl. The oxetanyl-containing groups are exemplified byethyloxetanyloxy. The acyl is exemplified by acetyl, propionyl, andbenzoyl. The halogen is exemplified by chlorine, bromine, and iodine.

The monovalent heterocyclic group may have one or more substituents. Thesubstituents are exemplified by the substituents which the monovalenthydrocarbon group may have.

More specifically, the monovalent hydrocarbon group and the monovalentheterocyclic group are exemplified by methyl, ethyl, propyl, isopropyl,butyl, hexyl, octyl, decyl, phenyl, naphthyl, anthryl, benzyl,phenethyl, pyridyl, furyl, thienyl, vinyl, allyl, styryl (e.g.,p-styryl), substituted hydrocarbon groups (e.g.,2-(3,4-epoxycyclohexyl)ethyl, 3-glycidylpropyl, 3-methacryloxypropyl,3-acryloxypropyl, N-2-(aminoethyl)-3-aminopropyl, 3-aminopropyl,N-phenyl-3-aminopropyl, 3-mercaptopropyl, and 3-isocyanatopropyl).

R^(a) to R^(f) in Formula (I) may be identical or different.

In Formula (I), R^(g) represents, independently in each occurrence, adivalent hydrocarbon group. The divalent hydrocarbon group isexemplified by straight or branched chain alkylene (e.g., a grouprepresented by —[CH₂]_(t)—, where t represents an integer of 1 or more);and a divalent alicyclic hydrocarbon group. The straight or branchedchain alkylene is exemplified by C₁-C₁₈ straight or branched chainalkylene such as methylene, methylmethylene, dimethylmethylene,ethylene, propylene, and trimethylene. The divalent alicyclichydrocarbon group is exemplified by divalent cycloalkylene (includingcycloalkylidene) such as 1,2-cyclopentylene, 1,3-cyclopentylene,cyclopentylidene, 1,2-cyclohexylene, 1,3-cyclohexylene,1,4-cyclohexylene, and cyclohexylidene. Among them, R^(g) is preferably,independently in each occurrence, straight or branched chain alkylene.

In Formula (I), s1 represents an integer of 1 or more. When s1 is aninteger of 2 or more, two or more occurrences of the structure in thebrackets with s1 may be identical or different. When the structureincludes two or more different structures in the brackets with s1, thestructures may be added to each other in a manner not limited.Typically, the structures may be added to each other in a random formand/or a block form.

In Formula (I), s2 represents an integer of 1 or more. When s2 is aninteger of 2 or more, two or more structures in the brackets with s2 maybe identical or different. When two or more different structures arepresent in the brackets with s2, the structures may be added to eachother in a manner not limited. Typically, the structures may be added toeach other in a random form and/or a block form.

In Formula (I), the structure in the brackets with s1 and the structurein the brackets with s2 may be added to each other in a manner notlimited. Typically, the structures may be added to each other in arandom form and/or a block form.

The polyorganosiloxysilalkylene may contain a terminal structure notlimited, but exemplified by silanol group, alkoxysilyl, andtrialkylsilyl (e.g., trimethylsilyl). The polyorganosiloxysilalkylenemay include, at its terminus or termini, a variety of groups such as agroup containing an aliphatic carbon-carbon double bond; and hydrosilylgroup.

The polyorganosiloxysilalkylene having the structure represented byFormula (I) may have either a straight chain structure or a branchedchain structure, as mentioned above.

The polyorganosiloxane (A) in the curable resin composition according tothe present invention may contain the polyorganosiloxysilalkylene in aproportion not critical, but preferably 60 percent by weight or more(e.g., from 60 to 100 percent by weight), more preferably 80 percent byweight or more (e.g., from 80 to 99.5 percent by weight), and morepreferably 90 percent by weight or more, based on the total amount (100percent by weight) of the polyorganosiloxane (A). The polyorganosiloxane(A), if containing the polyorganosiloxysilalkylene in a proportion lessthan 60 percent by weight, may readily cause the cured product to besusceptible to yellowing and/or to readily have surface tack to therebyoffer inferior handleability.

Polyorganosiloxane (A1) Containing Aliphatic Carbon-Carbon Double Bond

The polyorganosiloxane (A) in the curable resin composition according tothe present invention may include a polyorganosiloxane (A1). The“polyorganosiloxane (A1)” herein refers to a polyorganosiloxane (A)containing an aliphatic carbon-carbon double bond. The aliphaticcarbon-carbon double bond may be present in a substituent in thepolyorganosiloxane (A1). The substituent is exemplified by a substituenton a silicon atom. The aliphatic carbon-carbon double bond may also bepresent at a terminus of the main chain (straight chain and/or branchedchain) of the polyorganosiloxane (A1), where the main chain includessiloxane bonds (Si—O—Si).

A group containing the aliphatic carbon-carbon double bond isexemplified by C₂-C₂₀ alkenyl such as vinyl, allyl, methallyl,1-propenyl, isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl,2-pentenyl, 3-pentenyl, 4-pentenyl, and 5-hexenyl, of which C₂-C₁₀alkenyl is preferred, and C₂-C₄ alkenyl is more preferred; C₃-C₁₂cycloalkenyl such as cyclohexenyl; C₄-C₁₅ bridged unsaturatedhydrocarbon groups such as bicycloheptenyl; (C₂-C₄ alkenyl)-substitutedaryl such as styryl; and cinnamyl. The group containing the aliphaticcarbon-carbon double bond also includes the group represented by Formula(4) in which at least one of the three occurrences of R′ is theabove-mentioned group such as C₂-C₂₀ alkenyl, C₃-C₁₂ cycloalkenyl,C₄-C₁₅ bridged unsaturated hydrocarbon groups, C₂-C₄ alkenyl-substitutedaryl, and cinnamyl. Among them, alkenyl is preferred, C₂-C₂₀ alkenyl ismore preferred, and vinyl is furthermore preferred.

The curable resin composition according to the present inventionpreferably includes a polyorganosiloxysilalkylene containing analiphatic carbon-carbon double bond in molecule as thepolyorganosiloxane (A1). The polyorganosiloxysilalkylene is exemplifiedby a polyorganosiloxysilalkylene containing, at its terminus and/or sidechain, a group containing an aliphatic carbon-carbon double bond. Morespecifically, the polyorganosiloxysilalkylene is exemplified by apolyorganosiloxysilalkylene that contains, at its terminus and/or sidechain, a group containing an aliphatic carbon-carbon double bond andincludes a structure represented by Formula (I); and apolyorganosiloxysilalkylene including a structure represented by Formula(I) in which at least one occurrence of R^(a) to R^(f) is a monovalentgroup containing an aliphatic carbon-carbon double bond.

The polyorganosiloxane (A) may contain the aliphatic carbon-carbondouble bond in a content (in terms of vinyl) not critical, butpreferably from 1.5 to 15.0 percent by weight, more preferably from 2.0to 13.0 percent by weight, and furthermore preferably from 3.0 to 12.0percent by weight, based on the total amount (100 percent by weight) ofthe polyorganosiloxane (A). The polyorganosiloxane (A), when containingthe aliphatic carbon-carbon double bond in a content within the range,may readily allow the resulting cured product to excel in heatresistance and other physical properties, cracking resistance, andbarrier properties to a corrosive gas. The content of the aliphaticcarbon-carbon double bond may be measured typically by ¹H-NMR.

The curable resin composition according to the present inventionpreferably includes, as the polyorganosiloxane (A1) and as an essentialcomponent, a polyorganosiloxane (A1) having an aliphatic carbon-carbondouble bond content (in terms of vinyl) of 10.0 percent by weight ormore (e.g., from 10.0 to 20.0 percent by weight). The curable resincomposition, when containing the polyorganosiloxane (A1) of this type asan essential component, may readily allow the cured product to haveremarkably better barrier properties to a corrosive gas and to exhibitsuch excellent barrier properties for a longer period of time.

The polyorganosiloxane (A1) having an aliphatic carbon-carbon doublebond content (in terms of vinyl) of 10.0 percent by weight or more has aweight-average molecular weight of preferably 2000 or less (e.g., from500 to 2000), and more preferably 1600 or less; and has a number-averagemolecular weight of preferably 1000 or less (e.g., from 400 to 1000),and more preferably 900 or less. In an embodiment, thepolyorganosiloxane (A1) having an aliphatic carbon-carbon double bondcontent (in terms of vinyl) of 10.0 percent by weight or more has aweight-average molecular weight of 2000 or less and/or a number-averagemolecular weight of 1000 or less. The curable resin composition, whenincluding this polyorganosiloxane (A1), may readily allow the curedproduct to have remarkably better barrier properties to a corrosive gasand to exhibit such excellent barrier properties for a still longerperiod of time.

The polyorganosiloxane (A) may contain the polyorganosiloxane (A1)having an aliphatic carbon-carbon double bond content (in terms ofvinyl) of 10.0 percent by weight or more in a proportion of preferablyfrom 1 to 10 percent by weight, and more preferably from 2 to 8 percentby weight, based on the total amount (100 percent by weight) of thepolyorganosiloxane (A), where the polyorganosiloxane (A1) is preferablyone having a weight-average molecular weight of 2000 or less and/or anumber-average molecular weight of 1000 or less. Control of theproportion within the range may allow the curable resin composition toreadily allow the cured product having strength and barrier propertiesto a corrosive gas both at satisfactorily levels.

Polyorganosiloxane (A2) Containing Si—H Bond

The polyorganosiloxane (A) in the curable resin composition according tothe present invention may include a polyorganosiloxane (A2). The“polyorganosiloxane (A2)” refers to a polyorganosiloxane (A) containinga Si—H bond. The Si—H bond may be present in a substituent in thepolyorganosiloxane (A2). The substituent is exemplified by a substituenton the silicon atom. The Si—H bond may also be present at a terminus ofthe main chain (straight chain and/or branched chain) of thepolyorganosiloxane (A2), where the main chain includes siloxane bonds(Si—O—Si).

A group containing the Si—H bond is exemplified by, but not limited to,a group represented by Formula (4) in which at least one of threeoccurrences of R′ is hydrogen.

The curable resin composition according to the present inventionpreferably includes, as the polyorganosiloxane (A2), apolyorganosiloxysilalkylene containing a hydrosilyl group (Si—H bond) inmolecule. The polyorganosiloxysilalkylene is exemplified by apolyorganosiloxysilalkylene containing, at its terminus and/or sidechain, hydrogen (hydrido) bonded to silicon. More specifically, thepolyorganosiloxysilalkylene is exemplified by apolyorganosiloxysilalkylene that contains, at its terminus and/or sidechain, hydrogen bonded to silicon and includes a structure representedby Formula (I); and a polyorganosiloxysilalkylene that includes astructure represented by Formula (I) in which at least one occurrence ofR^(a) to R^(f) is hydrogen.

The polyorganosiloxane (A) may contain the Si—H bond in a content interms of H not critical, but preferably from 0.01 to 0.50 percent byweight, more preferably from 0.05 to 0.30 percent by weight, andfurthermore preferably from 0.08 to 0.20 percent by weight, based on thetotal amount (100 percent by weight) of the polyorganosiloxane (A). Theterm “in terms of H” refers to “in terms of the weight of hydrogen or H(hydrido) in Si—H bond”. The polyorganosiloxane (A), when containing theSi—H bond in a content within the range, may readily allow the resultingcured product to excel in heat resistance and other physical properties,cracking resistance, and barrier properties to a corrosive gas. The Si—Hbond content may be measured typically by ¹H-NMR.

The polyorganosiloxane (A) may contain the polyorganosiloxane (A2) in acontent not critical, but preferably 50 percent by weight or more (e.g.,from 50 to 98 percent by weight), more preferably 80 percent by weightor more, and furthermore preferably 95 percent by weight or more, basedon the total amount (100 percent by weight) of the polyorganosiloxane(A). The polyorganosiloxane (A), when containing the polyorganosiloxane(A2) in a content within the range, may readily allow the resultingcured product to excel in heat resistance and other physical properties,cracking resistance, and barrier properties to a corrosive gas.

The polyorganosiloxane (A1) may act also as a Si—H-bond-containingpolyorganosiloxane (A2); whereas the polyorganosiloxane (A2) may alsoact as a polyorganosiloxane (A1) containing an aliphatic carbon-carbondouble bond.

The polyorganosiloxane (A) may include either one of thepolyorganosiloxane (A1) and the polyorganosiloxane (A2) alone. Thepolyorganosiloxane (A) may also include two or more differentpolyorganosiloxanes (A1) and/or two or more differentpolyorganosiloxanes (A2).

In an embodiment, the polyorganosiloxane (A) includes two or moredifferent polyorganosiloxanes, and at least one of the two or moredifferent polyorganosiloxanes is the polyorganosiloxane (A2). In thisembodiment, other polyorganosiloxane(s) excluding the polyorganosiloxane(A2) is preferably a polyorganosiloxane (A1) devoid of Si—H bonds.

Isocyanurate Compound (B) The curable resin composition according to thepresent invention includes an isocyanurate compound (B). The curableresin composition according to the present invention, as including theisocyanurate compound (B), particularly gives, when cured, a curedproduct having better barrier properties to a corrosive gas and offeringbetter adhesion to an adherend. In particular, the curable resincomposition preferably includes the isocyanurate compound represented byFormula (1) as the isocyanurate compound (B).

In Formula (1), R^(x), R^(Y), and R^(z) are each, identically ordifferently, selected from the group represented by Formula (2) and thegroup represented by Formula (3). In particular, one or more (preferablyone or two, more preferably one) of R^(x), R^(y), and R^(z) in Formula(1) is the group represented by Formula (3). The isocyanurate compoundrepresented by Formula (1) particularly preferably contains, as R^(x),R^(y), and R^(z), both the group represented by Formula (2) and thegroup represented by Formula (3). Specifically preferably in theisocyanurate compound represented by Formula (1), two of R^(x), R^(y),and R^(z) are the groups represented by Formula (2), and the other oneof R^(x), R^(Y), and R^(z) is the group represented by Formula (3). Thisis preferred so as to allow the cured product to have satisfactorybarrier properties to a corrosive gas.

In Formulae (2) and (3), R¹ and R² are each, identically or differently,selected from hydrogen and C₁-C₈ straight or branched chain alkyl. TheC₁-C₈ straight or branched chain alkyl is exemplified by methyl, ethyl,propyl, isopropyl, butyl, isobutyl, s-butyl, pentyl, hexyl, heptyl,octyl, and ethylhexyl. Of the alkyl, preferred is C₁-C₃ straight orbranched chain alkyl such as methyl, ethyl, propyl, and isopropyl. R¹and R² in Formulae (2) and (3) are each particularly preferablyhydrogen.

The isocyanurate compound (B) is exemplified by, but not limited to,monoallyl dimethyl isocyanurate, diallyl monomethyl isocyanurate,triallyl isocyanurate, monoallyl diglycidyl isocyanurate, diallylmonoglycidyl isocyanurate, triglycidyl isocyanurate,1-allyl-3,5-bis(2-methylepoxypropyl)isocyanurate,1-(2-methylpropenyl)-3,5-diglycidylisocyanurate,1-(2-methylpropenyl)-3,5-bis(2-methylepoxypropyl)isocyanurate,1,3-diallyl-5-(2-methylepoxypropyl)isocyanurate,1,3-bis(2-methylpropenyl)-5-glycidylisocyanurate,1,3-bis(2-methylpropenyl)-5-(2-methylepoxypropyl)isocyanurate, andtris(2-methylpropenyl)isocyanurate. The curable resin composition mayinclude each of different isocyanurate compounds alone or in combinationas the isocyanurate compound (B).

For better compatibility with another component, the isocyanuratecompound (B) may be mixed with the silane coupling agent (C) beforebeing mixed with the other component, as described above.

The curable resin composition may contain the isocyanurate compound (B)in a content not critical, but preferably from 0.01 to 10 percent byweight, more preferably from 0.05 to 5 percent by weight, furthermorepreferably from 0.1 to 3 percent by weight, and particularly preferablygreater than 0.5 percent by weight, based on the total amount (100percent by weight) of the curable resin composition. The curable resincomposition, if containing the isocyanurate compound (B) in a contentless than 0.01 percent by weight, may cause the cured product to havelower barrier properties to a corrosive gas and inferior adhesion to anadherend. In particular, the curable resin composition, when containingthe isocyanurate compound (B) in a content greater than 0.5 percent byweight (e.g., in a content from greater than 0.5 percent by weight to 10percent by weight), may readily allow the cured product to haveremarkably better barrier properties to a corrosive gas and to exhibitsuch excellent barrier properties for a longer period of time. Incontrast, the curable resin composition, if containing isocyanuratecompound (B) in a content greater than 10 percent by weight, may undergodeposition of a solid therein and/or may cause the cured product tobecome clouded.

Silane Coupling Agent (C)

The curable resin composition according to the present inventionincludes a silane coupling agent (C). The curable resin compositionaccording to the present invention, as including the silane couplingagent (C), gives, when cured, a cured product having better barrierproperties to a corrosive gas and, in particular, having better adhesionto an adherend.

The silane coupling agent (C) has good compatibility typically with thepolyorganosiloxane (A) and the isocyanurate compound (B). Typically, inan embodiment, the isocyanurate compound (B) is previously mixed withthe silane coupling agent (C) to give a composite, and the composite ismixed with another component or components. This contributes to bettercompatibility of the isocyanurate compound (B) with the other componentor components and may often give a homogeneous curable resincomposition.

The silane coupling agent (C) for use herein may be selected from knownor common silane coupling agents. Such silane coupling agents areexemplified by, but not limited to, epoxy-containing silane couplingagent such as 3-glycidoxypropyltrimethoxysilane,2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,3-glycidoxypropylmethyldiethoxysilane, and3-glycidoxypropyltriethoxysilane; amino-containing silane couplingagents such as N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane,N-2-(aminoethyl)-3-aminopropyltrimethoxysilane,N-2-(aminoethyl)-3-aminopropyltriethoxysilane,3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane,3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine,N-phenyl-3-aminopropyltrimethoxysilane,N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilanehydrochloride, and N-(β-aminoethyl)-γ-aminopropylmethyldiethoxysilane;and other silane coupling agents such as tetramethoxysilane,tetraethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane,methyltriethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane,vinyltris(methoxyethoxy)silane, phenyltrimethoxysilane,diphenyldimethoxysilane, vinyltriacetoxysilane,γ-(meth)acryloxypropyltriethoxysilane,γ-(meth)acryloxypropyltrimethoxysilane,γ-(meth)acryloxypropylmethyldimethoxysilane,γ-(meth)acryloxypropylmethyldiethoxysilane,mercaptopropylenetrimethoxysilane, and mercaptopropylenetriethoxysilane.Among them, the epoxy-containing silane coupling agents are preferablyusable, of which 3-glycidoxypropyltrimethoxysilane is more preferred.The curable resin composition may include each of different silanecoupling agents alone or in combination as the silane coupling agent(C).

The curable resin composition may contain the silane coupling agent (C)in a content not critical, but preferably from 0.01 to 15 percent byweight, more preferably from 0.1 to 10 percent by weight, furthermorepreferably from 0.5 to 5 percent by weight, and particularly preferablygreater than 2.0 percent by weight, based on the total amount (100percent by weight) of the curable resin composition. The curable resincomposition, if containing the silane coupling agent (C) in a contentless than 0.01 percent by weight, may cause the cured product to havelower adhesion to an adherend and may fail to exhibit sufficient effects(barrier properties to a corrosive gas) particularly when theisocyanurate compound (B) is mixed with the silane coupling agent (C)beforehand. In particular, the curable resin composition, whencontaining the silane coupling agent (C) in a content greater than 2.0percent by weight (e.g., in a content from greater than 2.0 percent byweight to 15 percent by weight), may readily allow the cured product tohave remarkably better barrier properties to a corrosive gas and toexhibit such excellent barrier properties for a longer period of time.In contrast, the curable resin composition, if containing the silanecoupling agent (C) in a content greater than 15 percent by weight, maybe cured insufficiently and may cause the cured product to have lowertoughness, heat resistance, and/or barrier properties to a corrosivegas.

Hydrosilylation Catalyst

The curable resin composition according to the present invention mayfurther include a hydrosilylation catalyst. The curable resincomposition according to the present invention, when further includingthe hydrosilylation catalyst, may allow a curing reaction(hydrosilylation reaction) to proceed efficiently. The hydrosilylationcatalyst may be selected from known catalysts for hydrosilylationreaction, such as platinum catalysts, rhodium catalysts, and palladiumcatalysts. Specifically, the hydrosilylation catalyst is exemplified byplatinum catalysts including fine platinum powder, platinum black,platinum supported on fine silica powder, platinum supported onactivated carbon, chloroplatinic acid, complexes of chloroplatinic acidwith an alcohol, an aldehyde, or a ketone, platinum-olefin complexes,platinum-carbonyl complexes (e.g., platinum-carbonylvinylmethylcomplex), platinum-vinylmethylsiloxane complexes (e.g.,platinum-divinyltetramethyldisiloxane complex andplatinum-cyclovinylmethylsiloxane complex), platinum-phosphinecomplexes, and platinum-phosphite complexes; and palladium catalysts andrhodium catalysts corresponding to the platinum catalysts, except forrespectively containing palladium atom and rhodium atom instead ofplatinum atom. The curable resin composition may include each ofdifferent hydrosilylation catalysts alone or in combination as thehydrosilylation catalyst.

The curable resin composition according to the present invention maycontain the hydrosilylation catalyst in a content not critical, but sucha content that the amount of platinum, palladium, or rhodium in thehydrosilylation catalyst falls typically in the range of preferably from0.01 to 1,000 ppm by weight, and more preferably from 0.1 to 500 ppm byweight. The curable resin composition, when containing thehydrosilylation catalyst in a content within the range, may not sufferfrom a remarkably low crosslinking rate and may not cause coloration andother disadvantages of the cured product, thus being preferred.

Hydrosilylation Inhibitor

The curable resin composition according to the present invention mayinclude a hydrosilylation inhibitor so as to control the speed (rate) ofcuring reaction (hydrosilylation reaction). The hydrosilylationinhibitor is exemplified by alkyne alcohols such as3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, and phenylbutynol;ene-yne compounds such as 3-methyl-3-penten-1-yne and3,5-dimethyl-3-hexen-1-yne; and other compounds such as thiazole,benzothiazole, and benzotriazole. The curable resin composition mayinclude each of different hydrosilylation inhibitors alone or incombination as the hydrosilylation inhibitor. The curable resincomposition may contain the hydrosilylation inhibitor in a contentwithin the range of practically preferably from 0.00001 to 5 percent byweight based on the total amount of the curable resin composition,although the content may vary depending on the crosslinking conditionsof the curable resin composition.

Silsesquioxane

The curable resin composition according to the present invention mayfurther include a silsesquioxane. The silsesquioxane is exemplified by,but not limited to, silsesquioxanes each having any of random structure,cage structure, and ladder structure, of which preferred aresilsesquioxanes including, as a principal component, a silsesquioxanehaving a ladder structure.

The “silsesquioxane” is a kind of polysiloxanes. Such polysiloxanes aregenerally compounds containing a main chain including siloxane bonds(Si—O—Si). Their basic constitutional units are exemplified by M unit, Dunit, T unit, and Q unit. The M unit refers to a unit including amonovalent group containing a silicon atom bonded to one oxygen atom.The D unit refers to a unit including a divalent group containing asilicon atom bonded to two oxygen atoms. The T unit refers to a unitincluding a trivalent group containing a silicon atom bonded to threeoxygen atoms. The Q unit refers to a unit including a tetravalent groupcontaining a silicon atom bonded to four oxygen atoms. Thesilsesquioxane is a polysiloxane including the T unit as a basicconstitutional unit and has an empirical formula (basic structuralformula) represented by RSiO_(1.5). The silsesquioxane includes aSi—O—Si skeleton having a structure selected typically from randomstructure, cage structure, and ladder structure. The above-mentionedladder-like silsesquioxane is a silsesquioxane structurally including aSi—O—Si skeleton having a ladder structure.

The silsesquioxane may contain two or more aliphatic carbon-carbondouble bonds in molecule (per molecule). The silsesquioxane may containtwo or more Si—H bond-containing groups in molecule (per molecule). Thesilsesquioxane is preferably, but not limitatively, liquid at roomtemperature. The curable resin composition may include each of differentsilsesquioxanes alone or in combination.

The curable resin composition according to the present invention,particularly when including one or more silsesquioxanes, may readilygive, when cured, a cured product having better barrier properties to acorrosive gas and offering better toughness (in particular, crackingresistance). The curable resin composition according to the presentinvention may contain the silsesquioxane(s) in a content (blendingquantity) not critical, but preferably from 0.01 to 30 percent byweight, more preferably from 0.1 to 20 percent by weight, andfurthermore preferably from 0.5 to 10 percent by weight, based on thetotal amount (100 percent by weight) of the curable resin composition.

Other Siloxane Compound

The curable resin composition according to the present invention mayfurther include, as another siloxane compound, a cyclic siloxanecontaining two or more aliphatic carbon-carbon double bonds in molecule(per molecule). The curable resin composition according to the presentinvention may further include, as another siloxane compound, a cyclicsiloxane containing two or more Si—H bonds in molecule (per molecule).The curable resin composition may include each of different cyclicsiloxanes as above alone or in combination. The curable resincomposition according to the present invention may contain the cyclicsiloxane(s) in a content (blending quantity) not critical, butpreferably from 0.01 to 30 percent by weight, more preferably from 0.1to 20 percent by weight, and furthermore preferably from 0.5 to 10percent by weight, based on the total amount (100 percent by weight) ofthe curable resin composition.

Other Silane Compound

The curable resin composition according to the present invention mayinclude another silane compound (e.g., a compound containing ahydrosilyl group). The other silane compound is exemplified by straightor branched chain siloxanes containing a Si—H group, such asmethyltris(dimethylsiloxy)silane, tetrakis(dimethylsiloxy)silane,1,1,3,3-tetramethyldisiloxane, 1,1,3,3,5,5-hexamethyltrisiloxane,1,1,1,3,5,5,5-heptamethyltrisiloxane,1,1,3,3,5,5,7,7-octamethyltetrasiloxane,1,1,1,3,5,5,7,7,7-nonamethyltetrasiloxane,1,1,3,3,5,5,7,7,9,9-decamethylpentasiloxane, and1,1,1,3,5,5,7,7,9,9,9-undecamethylpentasiloxane. The curable resincomposition may include each of different silane compounds alone or incombination. The curable resin composition may contain the silanecompound(s) in a content not critical, but preferably from 0 to 5percent by weight or less, and more preferably from 0 to 1.5 percent byweight, based on the total amount (100 percent by weight) of the curableresin composition.

Solvent

The curable resin composition according to the present invention mayinclude a solvent. The solvent is exemplified by conventionally knownsolvents such as toluene, hexane, isopropanol, methyl isobutyl ketone,cyclopentanone, and propylene glycol monomethyl ether acetate. Thecurable resin composition may include each of different solvents aloneor in combination.

Additives

The curable resin composition according to the present invention mayfurther include any of common additives as additional optionalcomponents. The additives are exemplified by fillers as mentioned below;stabilizers such as antioxidants, ultraviolet absorbers,photostabilizers, and thermal stabilizers; flame retardants such asphosphorus flame retardants, halogen flame retardants, and inorganicflame retardants; flame retardant promoters; reinforcing materials suchas other fillers; nucleating agents; coupling agents; lubricants; waxes;plasticizers; mold-release agents; impact modifiers; hue modifiers; flowimprovers; colorants such as dyestuffs and pigments; dispersing agents;antifoaming agents; defoaming agents; antimicrobial agents; antisepticagents (preservatives); viscosity modifiers; and thickeners. The fillersare exemplified by inorganic fillers such as precipitated silica,hydrous silica (wet silica), fumed silica, pyrogenic silica, titaniumoxide, alumina, glass, quartz, aluminosilicate, iron oxide, zinc oxide,calcium carbonate, carbon black, silicon carbide, silicon nitride, andboron nitride, as well as inorganic fillers prepared by treating thesefillers with any of organosilicon compounds such as organohalosilanes,organoalkoxysilanes, and organosilazanes; fine powders of organic resinssuch as silicone resins, epoxy resins, and fluorocarbon resins; andelectroconductive powders of metals such as silver and copper. Thecurable resin composition may include each of different additives aloneor in combination.

Curable Resin Composition

The curable resin composition according to the present invention mayhave a formulation (blending formulation) not critical, but preferablyhas such a formulation that the amount of aliphatic carbon-carbon doublebonds is preferably from 0.2 to 4 moles, more preferably from 0.5 to 1.5moles, and furthermore preferably from 0.8 to 1.2 moles, per mole ofhydrosilyl group present in the curable resin composition. The curableresin composition, when containing hydrosilyl groups and aliphaticcarbon-carbon double bonds in proportions controlled within the range,may readily allow the cured product to have still better heatresistance, transparency, flexibility, reflow resistance, and barrierproperties to a corrosive gas.

Though not limited, the curable resin composition according to thepresent invention may be prepared by stirring and mixing the individualcomponents at room temperature. The curable resin composition accordingto the present invention can be used as a one-part composition or amulti-part (e.g., two-part) composition. The one-part composition isprepared by mixing the individual components in advance and used asintact. The multi-part composition is used as storing two or morecomponents separately and mixing them in predetermined proportionsbefore use.

The curable resin composition according to the present invention ispreferably, but not limitatively, liquid at room temperature (about 25°C.). More specifically, the curable resin composition according to thepresent invention has a viscosity at 23° C. of preferably from 300 to20000 mPa·s, more preferably from 500 to 10000 mPa·s, and furthermorepreferably from 1000 to 8000 mPa·s. The curable resin composition, ifhaving a viscosity less than 300 mPa·s, may cause the cured product tohave lower heat resistance. In contrast, the curable resin composition,if having a viscosity greater than 20000 mPa·s, may be prepared andhandled with difficulty and may cause the cured product to contain airbubbles as remaining. The viscosity at 23° C. may be measured typicallyusing a rheometer (trade name Physica UDS-200, supplied by Anton PaarGmbH) and a cone and a plate with a cone diameter of 16 mm and a taperangle of 0° at a temperature of 23° C. and a number of revolutions of 20rpm.

Cured Product

The curable resin composition according to the present invention, whencured by a curing reaction (hydrosilylation reaction), can give a curedproduct. Hereinafter the resulting cured product is also referred to as“cured product according to the present invention”. The curing reactionmay be performed under any conditions that are not critical andselectable as appropriate from conventionally known conditions. However,from the viewpoint of reaction rate, the curing reaction is preferablyperformed at a temperature (curing temperature) of from 25° C. to 180°C. (more preferably from 60° C. to 150° C.) for a time (curing time) offrom 5 to 720 minutes. The cured product according to the presentinvention has excellent physical properties such as heat resistance,transparency, and flexibility, still offers excellent reflow resistance,such as cracking resistance and adhesion to a package, in a reflowprocess, and excels in barrier properties to a corrosive gas such as aSO_(X) gas.

Encapsulating Agent and Encapsulant

An encapsulating agent according to the present invention is anencapsulating agent including the curable resin composition according tothe present invention as an essential component. The encapsulating agentaccording to the present invention, when cured, gives an encapsulant(cured product) according to the present invention. The encapsulant hasexcellent physical properties such as heat resistance, transparency,flexibility and still offers excellent reflow resistance and barrierproperties to a corrosive gas. The encapsulant according to the presentinvention is therefore preferably usable as encapsulants forsemiconductor elements in semiconductor devices and, in particular, asencapsulants for optical semiconductor elements in optical semiconductordevices. Of such optical semiconductor elements, the encapsulant isparticularly preferably usable as encapsulants for optical semiconductorelements with high brightness and short wavelength. The encapsulantaccording to the present invention, when used for the encapsulation of asemiconductor element (in particular, an optical semiconductor element),gives a semiconductor device (in particular, an optical semiconductordevice) that has excellent durability and quality.

EXAMPLES

The present invention will be illustrated in further detail withreference to several examples below. It should be noted, however, thatthe examples are by no means intended to limit the scope of the presentinvention.

Products were subjected to ¹H-NMR analyses using the JEOL ECA500 (500MHz). The products were also subjected to measurements of number-averagemolecular weight and weight-average molecular weight using the AllianceHPLC System 2695 (supplied by Waters Corporation), Refractive IndexDetector 2414 (supplied by Waters Corporation), two Tskgel GMH^(HR)-Mcolumns (supplied by Tosoh Corporation), the Tskgel guard column H^(HR)L(supplied by Tosoh Corporation) as a guard column, the COLUMN HEATERU-620 (supplied by Sugai) as a column oven, and THF as a solvent at ameasurement temperature of 40° C.

Polyorganosiloxane (A)

The polyorganosiloxane (A) used herein is any of products as follows:

OE-6665A: Product supplied by Dow Corning Toray Co., Ltd., having avinyl content of 11.97 percent by weight, a phenyl content of 21.39percent by weight, a SiH content (in terms of hydrido) of 0 percent byweight, a number-average molecular weight of 831, and a weight-averagemolecular weight of 1455

OE-6665B: Product supplied by Dow Corning Toray Co., Ltd. and having avinyl content of 3.76 percent by weight, a phenyl content of 48.58percent by weight, a SiH content (in terms of hydrido) of 0.16 percentby weight, a number-average molecular weight of 744, and aweight-average molecular weight of 1274

GD-1130A: Product supplied by Eternal. Chemical Co., Ltd. and having avinyl content of 4.32 percent by weight, a phenyl content of 44.18percent by weight, a SiH content (in terms of hydrido) of 0 percent byweight, a number-average molecular weight of 1107, and a weight-averagemolecular weight of 6099

GD-1130B: Product supplied by Eternal Chemical Co., Ltd. and having avinyl content of 3.45 percent by weight, a phenyl content of 50.96percent by weight, a SiH content (in terms of hydrido) of 0.17 percentby weight, a number-average molecular weight of 631, and aweight-average molecular weight of 1305

ASP-1120A: Product supplied by Shin-Etsu Chemical Co., Ltd. and having avinyl content of 5.94 percent by weight, a phenyl content of 64.61percent by weight, a SiH content (in terms of hydrido) of 0 percent byweight, a number-average molecular weight of 590, and a weight-averagemolecular weight of 780

ASP-1120B: Product supplied by Shin-Etsu Chemical Co., Ltd. and having avinyl content of 3.31 percent by weight, a phenyl content of 49.08percent by weight, a SiH content (in terms of hydrido) of 0.30 percentby weight, a number-average molecular weight of 680, and aweight-average molecular weight of 1320

OE-6630A: Product supplied by Dow Corning Toray Co., Ltd. and having avinyl content of 2.17 percent by weight, a phenyl content of 51.94percent by weight, a SiH content (in terms of hydrido) of 0 percent byweight, a number-average molecular weight of 2532, and a weight-averagemolecular weight of 4490

OE-6630B: Product supplied by Dow Corning Toray Co., Ltd. and having avinyl content of 3.87 percent by weight, a phenyl content of 50.11percent by weight, a SiH content (in terms of hydrido) of 0.17 percentby weight, a number-average molecular weight of 783, and aweight-average molecular weight of 1330

KER-2500A: Product supplied by Shin-Etsu Chemical Co., Ltd. and having avinyl content of 1.53 percent by weight, a phenyl content of 0 percentby weight, a SiH content (in terms of hydrido) of 0.03 percent byweight, a number-average molecular weight of 4453, and a weight-averagemolecular weight of 19355

KER-2500B: Product supplied by Shin-Etsu Chemical Co., Ltd. and having avinyl content of 1.08 percent by weight, a phenyl content of 0 percentby weight, a SiH content (in terms of hydrido) of 0.13 percent byweight, a number-average molecular weight of 4636, and a weight-averagemolecular weight of 18814

GD-1012A: Product supplied by Eternal Chemical Co., Ltd. and having avinyl content of 1.33 percent by weight, a phenyl content of 0 percentby weight, a SiH content (in terms of hydrido) of 0 percent by weight, anumber-average molecular weight of 5108, and a weight-average molecularweight of 23385

GD-1012B: Product supplied by Eternal Chemical Co., Ltd. and having avinyl content of 1.65 percent by weight, a phenyl content of 0 percentby weight, a SiH content (in terms of hydrido) of 0.19 percent byweight, a number-average molecular weight of 4563, and a weight-averagemolecular weight of 21873

EXAMPLES AND COMPARATIVE EXAMPLES

Examples 1 to 5 and Comparative Examples 1 to 10 were performed by aprocedure as follows.

In accordance with Tables 1 and 2, an isocyanurate compound (B) and asilane coupling agent (C) were mixed in a predetermined weight ratio togive a mixture, the mixture was further combined withpolyorganosiloxanes (A), stirred at room temperature for 2 hours, andyielded a transparent solution. The blending quantities of individualcomponents in Tables 1 and 2 are indicated in part by weight. Thesolution was combined with 1.3 μl of a 2.0% platinum-cyclovinylsiloxanecomplex vinylcyclosiloxane solution (supplied by Wako Pure ChemicalIndustries, Ltd.), stirred for further 30 minutes, and yielded a curableresin composition.

The above-prepared curable resin composition was applied to a glassplate, heated at a predetermined temperature for a predetermined timeaccording to curing conditions given in Tables 3 and 4, and yielded acolorless, transparent cured product in each of the examples andcomparative examples.

The column “Mw/Mn” in Tables 1 and 2 indicates the average ofweight-average molecular weights (Mw), the average of number-averagemolecular weights (Mn), and the ratio of the average of weight-averagemolecular weights (Mw) to the average of number-average molecularweights (Mn) in the polyorganosiloxanes (A) used in each of the examplesand comparative examples.

TABLE 1 Examples 1 2 3 4 5 Mw/Mn Polyorganosi- OE-6665A 10 1283/748 =1.72 loxane (A) OE-6665B 200 GD-1130A 25 25 2264/726 = 3.10 GD-1130B 100100 ASP-1120A 100 1050/635 = 1.65 ASP-1120B 100 OE-6630A 50 1962/1133 =1.73  OE-6630B 200 Isocyanurate Monoallyl diglycidyl isocyanurate 0.60.3 0.4 0.5 — compound (B) Triallyl isocyanurate 0.3 — Silane coupling3-Glycidyloxypropyltrimethoxysilane 2.4 1.0 1.0 1.6 2.0 — agent (C)

TABLE 2 Comparative Examples 1 2 3 4 5 6 7 8 9 10 Mw/Mn Polyorganosi-OE-6665A 10 1283/748 = 1.72 loxane (A) OE-6665B 200 GD-1130A 25 25 252264/726 = 3.10 GD-1130B 100 100 100 ASP-1120A 100 1050/635 = 1.65ASP-1120B 100 OE-6630A 50 1962/1133 = 1.73  OE-6630B 200 KER-2500A 100100 19085/4545 = 4.20  KER-2500B 100 100 GD-1012A 100 100 22629/4836 =4.68  GD-1012B 100 100 Isocyanurate Monoallyl diglycidyl isocyanurate0.4 0.4 — compound (B) Triallyl isocyanurate 1.3 — Methyl diglycidylisocyanurate 1.3 — Silane coupling 3-Glycidyloxypropyltrimethoxysilane1.6 1.6 — agent (C)

Sulfur Corrosion Test

Each of the curable resin compositions prepared in Examples 1 to 5 andComparative Examples 1 to 10 was poured into an LED package (TOP LEDOP-3, 35 mm by 28 mm, without element), heated at a predeterminedtemperature for a predetermined time in accordance with curingconditions given in Tables 3 and 4, and yielded a sample.

The sample and 0.3 g of a sulfur powder (supplied by KISHIDA CHEMICALCo., Ltd.) were placed in a 450-ml glass bottle, and the glass bottlewas further placed in an aluminum case. Next, the aluminum case wasplaced in an oven (supplied by Yamato Scientific Co., Ltd., model numberDN-64), the oven temperature was set at 80° C., and how the silverelectrode in the LED package of the sample was corroded was observed 24hours, 48 hours, and 72 hours later. The electrode appears silvery whitebefore the test, but, when corroded, changes in color to dark brown, andfurther to black with the progress of corrosion. The criteria in thesulfur corrosion test are as follows. A sample undergoing little changein color in the silver electrode was evaluated as “A”; a sampleundergoing a partial change in color to dark brown or black wasevaluated as “B”; and a sample undergoing a full change in color to darkbrown or black was evaluated as “C”. Results are indicated in Tables 3and 4.

Surface Tack Test

Each of the cured products prepared in Examples 1 to 5 and ComparativeExamples 1 to 10 was evaluated on surface tack. The surface tack testwas performed according to the criteria as follows. A sample curedproduct offering little tackiness on its surface was evaluated as “A”;and a sample cured product offering tackiness on its surface wasevaluated as “B”. Results are indicated in Tables 3 and 4.

TABLE 3 Examples 1 2 3 4 5 Sulfur 24 hrs later A A A A A corrosion 48hrs later A A B A A test 72 hrs later A B C B B Surface tack test B A AB B Curing conditions 150° C. (2 80° C. (1 80° C. (1 100° C. (1 150° C.(2 hrs) hr) then hr) then hr) then hrs) 150° C. (4 150° C. (4 150° C. (4hrs) hrs) hrs)

TABLE 4 Comparative Examples 1 2 3 4 5 6 7 8 9 10 Sulfur 24 hrs later AA A A B C C C C C corrosion 48 hrs later B B C C C C C C C C test 72 hrslater C C C C C C C C C C Surface tack test B A A A B B B B A A Curingconditions 150° C. (2 80° C. (1 80° C. (1 80° C. (1 100° C. (1 150° C.(2 100° C. (1 100° C. (1 100° C. (1 100° C. (1 hrs) hr) then hr) thenhr) then hr) then hrs) hr) then hr) then hr) then hr) then 150° C. (4150° C. (4 150° C. (4 150° C. (4 150° C. (4 150° C. (4 150° C. (4 150°C. (4 hrs) hrs) hrs) hrs) hrs) hrs) hrs) hrs)

As demonstrated in Tables 3 and 4, the cured products (encapsulants)prepared in Examples 1 to 5 had better barrier properties to a corrosivegas as compared with those prepared in Comparative Examples 1 to 10. Inparticular, an example and a comparative example having an identicalformulation of the polyorganosiloxanes (A) were compared with eachother. Specifically, Example 1 was compared with Comparative Example 1,Examples 2 and 3 were compared with Comparative Examples 2 to 4, Example4 was compared with Comparative Example 5, and Example 5 was comparedwith Comparative Example 6. In these comparisons, the example(s) hadsignificantly better barrier properties to a corrosive gas as comparedWith the corresponding comparative example(s) particularly 48 hours and72 hours after the initiation of test. In addition, Table 3 demonstratesthat the samples according to Examples 2 and 3 usingpolyorganosiloxysilalkylenes as the polyorganosiloxanes (A) could givecured products that had little surface tack and offered excellenthandleability.

INDUSTRIAL APPLICABILITY

The curable resin composition and cured product according to the presentinvention are useful particularly in adhesives, coating agents,encapsulants, and other uses that require heat resistance, transparency,and barrier properties to a corrosive gas. In particular, the curableresin composition and cured product according to the present inventionare suitable as encapsulants for optical semiconductor elements such aslight-emitting diodes (LEDs), semiconductor laser elements, solarphotovoltaic elements, and charge coupled devices (CCDs).

1.-17. (canceled)
 18. A curable resin composition comprising: apolyorganosiloxane (A); an isocyanurate compound (B); and a silanecoupling agent (C), the polyorganosiloxane (A) being an aryl-containingpolyorganosiloxane, the aryl-containing polyorganosiloxane having: anumber-average molecular weight (Mn) of from 500 to 4000 as determinedby gel permeation chromatography and calibrated with a polystyrenestandard; and a molecular-weight dispersity (Mw/Mn) of from 0.95 to4.00, where the aryl-containing polyorganosiloxane has a weight-averagemolecular weight of Mw and a number-average molecular weight of Mn asdetermined by gel permeation chromatography and calibrated with apolystyrene standard, the polyorganosiloxane (A) comprising: apolyorganosiloxane (A1) comprising an aliphatic carbon-carbon doublebond; and a polyorganosiloxane (A2) comprising a Si—H bond, thepolyorganosiloxane (A) comprising 50 percent by weight or more of thepolyorganosiloxane (A2) comprising a Si—H bond based on the total amount(100 percent by weight) of the polyorganosiloxane (A), and theisocyanurate compound (B) comprising an isocyanurate compoundrepresented by Formula (1): [Chem. 1]

wherein R^(x), R^(y), and R^(z) are each, identically or differently,selected from a group represented by Formula (2) and a group representedby Formula (3), where at least one of R^(x), R^(y), and R^(z) is thegroup represented by Formula (3):

wherein R¹ and R² are each, identically or differently, selected fromhydrogen and C₁-C₈ straight or branched chain alkyl.
 19. A cured productof the curable resin composition according to claim
 18. 20. Anencapsulant obtained by using the curable resin composition according toclaim
 18. 21. A semiconductor device obtained by using the curable resincomposition according to claim 18.